Auxiliary hydraulic device for presses



Aug. 23, 1938. H. F. M MlLLlN 2,128,152

AUXILIARY-HYDRAULIC DEVICE FOR PRESSES Filed Aug. 16, 1934 s Sheets-Shet 1 A TTORA/EYS Aug. 23, 1938. H. F. M MlLLlN AUXILIARY HYDRAULIC DEVICE FOR PRESSES Filed Aug. 16, 1954 5 Sheets-Sheet 2 H. F. M MILLIN AUXILIARY HYDRAULIC DEVICE FOR PRESSES Aug. 23, 1938.

5 Sheets-Sheet 5 Filed Aug. 16, 1954 Aug. 23, 1938- H. F. MacMILLIN AUXILIARY HYDRAULIC DEVICE FOR PRESSES Filed Aug. 16, 1954 5 Sheets-Sheet 5 M/Vf/VTOR #014491? I: MAGM/lLl/V. :Y a

ATTORNEYS Patented Aug. 23, 1938 UNITED STATES PATENT. OFFICE AUXILIARY HYDRAULIC DEVIOE FOR PRESSES Howard F. MacMiilin, Mount Gilead Ohio, assignor, by memo assignments, to The Hydraulic Press Corporation, Inc., Wilmington, Del., a corporation of Delaware Application August 16, 1934, Serial Ne. 740,148

10 Claims.

by non-hydraulic mechanism, means for giving the press a hydraulic effect and hydraulic'pressure control.

give a pressure-controlled pressing effect: this,

auxiliary hydraulic ram being located in any desired place,such as in the platen orthe bed of the press.

Another object is to provide a platen-operated hydraulic generating arrangement of the abovementioned type, the auxiliary hydraulic ram and the hydraulic generator rams being of a double acting nature so that the upward motion of the main platen retracts the auxiliary hydraulic ram.

In the drawings:

Figure 1 is a front elevation, partly in section, of a press embodying single-acting hydraulic generator rams and a single-acting auxiliary hydraulic ram;

Figure 2 is a side elevation of the press shown in Figure 1, partly in section, along the line 22 of Figure 1;

Figure 3 is a horizontal section'along the line 3-3 of Figure 1;

Figure 4 is a front elevation, partly in section, of a portion of the press shown in Figure 1, but illustrating the use of double-acting generator rams in connection with a double-acting auxiliary hydraulic ram;

Figure 5 is a View similar to Figure 1, but with (or. looo) the auxiliary pressing cylinder located in the bed of the press instead of in the platen;

Figure 6 is a diagrammatic view of a circuit whereby the pressing ram in Figure 4 may be lifted with the assistance of an external source of pressure, such as air;

Figure 7 is a front elevation partly in section of a hydraulic circuit whereby the press may be given a. two-stage-eifect through a booster action contributed by the generator pistons;

Figure 8 is a vertical section through a pilotoperated check valve employed in the present circuit.

Press with single-acting generator rams- Refe'rring to the drawings; in detail, Figure 1 shows a press havinsiia, base Joined" by side members 2 to the top'niember 8, asby'the strain rods 4 on which are .threadedithe nuts 5. .Mount 6 ed on the base I ma work table or bed 8.,

The side members" 2:: of the press are equipped v with guide portions 1 adaptedto receive a press platen 8 for longitudinal reciprocation. The keeping of the platen 8 in engagement with the guide portion 1 is assisted by the retaining plates 9 bolted to the side. members 2 of the press.

The press platen 8 may be movedin any convvenient manner, such as mechanically .or hydraulically. For purposes of illustration, a geardriven mechanical crank press is shown, but other types may be used without departing from the scope of my invention.

In the form of. press shown, the platen 8 is provided with a cross shaft l0 journaled in bearings II on the upper portion of the platen 8.

Pivotally engaging the cross shaft I0 of the platen 8 is a connecting rod I! having a lower bearing l3, surrounding the cross shaft l0. At its upper end, the connecting rod I2 is provided with an upper bearing I4, which surrounds the crank portion ii of the main drive shaft Iii. The latter is journaled in bearings I1, mounted upon the side members 2 of the press.

The driving end of the main drive shaft I6 is provided with a gear l8 for this purpose. The gear I8 is connected by a clutch mechanism within the clutch housing IS in such a manner that the gear l8 may be connected or disconnected from the main drive shaft I6, as desired. The clutch mechanism within the clutch housing I9 is actuated by the crank arm 20 mounted on the clutch shaft 2| and connected by the link 22 to the pedal rod 23. The latter is reciprocably supported in the bosses 24 attached to one of the by the pivotal connection 25 to the foot pedal 25. By depressing or releasing the footpedal 28, the gear l8 may be made to operatively engage the main drive'shaft It, or rotate loosely-upon it. in this manner, the foot pedal 28.controls the press to provide for its executing working strokes or for its remaining idle, as may be desired.

The gear I8 is driven by a pinion 21, meshing therewith, and mounted upon the countershaft 28 journaled in the bearings 28 attached to the side members 2. The Opposite end of the countershaft 28 from the pinion 21 bears f'a flywheel 38 and a pulley 31, whereby the press maybe drivenfas from an electric motor belted to this pulley. Accordingly, when the pulley 3| is thus rotated, the gearl8 also rotates loosely upon the main drive shaft It. When the foot pedal 28 is depressed, the gear 18 drivingly engages the main shaft l8 and causes the crank portion 15 thereof to move in an orbital path. This movement causes the connecting rod l2 to move up and down, carrying with it the platen 8.

The platen 8 in its lower portion is provided with a pair of generator cylinder bores 32, and an auxiliary pressing cylinder bore 33. These cylinder bores are connected at their upper ends by the passages 34. Reciprocably mounted within the cylinder bores 32 are hydraulic generator rams 35, having their lower ends-secured in sock-- ets 36 in the base I (Figure 1). Leakage from the generator cylinders 32 is prevented by the provision of the packings 31, adapted to be compressed by glands 38. I

Mounted for reciprocation in the auxiliary pressing cylinder bore 33 is the auxiliary pressing ram 38, having an upper'enlarg ed portion 48 and a lower reduced portion 4|. Surrounding the reduced portion 4| is a coil spring 42, which is engaged by the enlarged head 48, thus providing for retraction of the auxiliary pressing ram 39,

' when the platen 8 moves upward. Leakage from the cylinder bore 33 is prevented by the packing 43, engaged by the gland 44, which surrounds the reduced portion 41 of the auxiliary pressing ram 39. v

To regulate the pressure developed in the operation of the press, as well as to replenish the fluid required, the generator plungers 35 are provided with longitudinal bores 85 which communicate by the pipe lines 88 with the pressure regulating valve 81. In the present embodiment (Figure 1) this valve is preferably of the type shown in the copending application of Ernst, Serial No. 669,493, now Patent No. 2,086,295, dated r July 6, 1937. Connected to the opposite side of the pressure regulating valve 8 1 by the line 88 is the check valve 88, which permits fluid to pass through itself toward the pressure regulating valve 81, but not in the opposite direction, The pipe lines 88 and 81 run from the remaining ports respectively of the pressure regulating valve 81 and check valve 88 to the make-up" tank 82. The latter contains fluid under a low pressure, such as under a gravity head or low air pressure, and supplies replenishment fluid to the generator cylinders 32, in the manner described below. A similar arrangement is used with the press shown in Figure 4.

' 35. This pressure fluid moves through the pas- ,sages 34 into the-auxiliary pressing cylinder 33, I

causing the auxiliary pressing ram 38 to'move downwardly. Thus the auxiliary pressing ram 38 is a positive-acting hydraulic plunger which performs actual pressing work by moving positively forward against the load, rather than a mere cushioning device which recedesunder the load.

The pressure regulating valve 81 is so loaded as to discharge fluid from line 88 into line 88 during the working stroke, when a predetermined pressure is reached in the space above the auxiliary pressing ram head 48. On the upward or return stroke of the press, the check valve .88 permits this discharged fluid to be returned from the make-up tank 82 to the lines-88 by way of the occurs with the press shown" fluid from the auxiliary pressing cylinder 33. The

energy stored in the compressed coil spring 42 then comes into play to retract the auxiliary pressing ram 38 by forcing it upwardly into its normal position of rest.

v Press with double-acting pressure generating rwms and auxiliary pressing rams designated by the same numerals. The regulation and replenishment circuit is as in Figure 1.

The auxiliary pressing ram 45. (Figure 4) is provided with an enlarged head 48 and a reduced stem 48. The cylinder bores 32 and 33 are connected above the enlarged head 48 by the upper passages 58; and below the enlarged head 48 by the lower passages 5|. The latter also are located below the lowermost positions of the intenslfler piston heads 41. r l I In the operation of the arrangement shown in Figure 4, as the platen 8 descends, the downwardly moving cylinder bores 32 cause the" fluid to be placed underpressure by their engagement with the fixed pressure generating piston, heads 41. .This pressure fluid is forced through the upper passages 58 into the auxiliary pressing bore 33, causing the auxiliary pressing ram 45 to move downwardly and forwardly against the load, thus positively exerting its force upon the work piece. When the platen 8 has completed its working stroke and starts its return stroke, the intensi fler cylinder bores 32 move upwardly relative to the intensifier piston heads 41. The fluid above the enlarged head 48 of the auxiliary pressing ram 451s thus drawn into the space above the pressure generating piston heads 41. At the same time, the fluid entrapped below the intensifier piston heads 41 is forced outward through the lower passages 5| into the space beneath the en- ,larged head 48 of the auxiliary pressing ramr45. This causes the head 48 to rise, retracting the auxiliary pressing ram 45. The action of thepressure regulating valve 81 and the replenishment circult is the same as previously described for Figure 1.

It will befurther understood, from'Figure 6,

that the pressing plunger 48 of Figure 4 may be retracted by means of pressure applied to the replenishment fluid in the make-up tank .92, the plunger 46 being provided with the twin longitudinal bores I23 and in opening respectively into the space above and beneath the piston head 41. The pressure regulating valve 81 and the check valve 89 are similar in construction and operation to those in Figure 4. The fluid in the make-up tank 92 (Figure 6) is subjected, as by compressed air, to pressure high enough to balance the weight of the hydraulic pressing ram 49. It will be further understood that the auxiliary pressing ram may be placed in the press bed, as in Figure 5, instead of in the platen.

Press with two-stage effect from external 'circuit and generator rams The press arranged according to the circuit shown in Figure 7 provides a two-stage effect. To accomplish this, the hydraulic pump 64 provides fluid to advance the pressing ram 49 rapidly disclosed in the copending application of Ernst,

Serial No. 669,493, .now Patent No. 2,086,295, dated July 6, 1937. Between these is arranged a pilot-operated check valve 95 having a valveopening plunger operated by fluid reaching it through the line I03 and normally permitting fluid to go from valve 9.4 to valve 93, but forcibly opened under certain circumstances, hereinafter described, to permit fluid to go in the opposite direction. This check valve 95 may be of any conventional type, the type shown being described in more detail below.

Y From the bore 59 of the generator piston 51, the line 96 leads to one side of the high pressure regulating valve93, from the opposite side of which the line 91 leads to the check valve 95 and the pilot line 98 leads to the pilot port of the pump unloading valve 94. From the opposite side of the check valve 95,the line 99 leads to a main chamber port of the pump unloading valve 94, to the opposite side of which is connected. the line 60 from the pump 64, From the discharge ports of the valves 93 and 94 run the discharge lines I and IM respectively, joining the common dis charge line I02 which runs back to the supply tank.

To complete the circuit, the line 6| from the opposite side of the pump 64 is connected to the bore 59 of the plunger 56, whence a pilot branch I03 continues onward to the pilot port of the check valve 95.

.The pipes 60 and 6| lead to the opposite ports 62 and 63, respectively, of thehydraulic pump 64. The latter is of a variable delivery type having a flow-control rod 65, which when moved in or out, varies the quantity and direction of the pressure fluid passing through the pipes 60 and 6I. The flow-control rod 65 is connected by the link 66 to one arm of the bell-crank 61, the other arm thereof being connected by the link 68 to the cam' push rod 69. This rod 69 is reciprocably mounted in the bearings 10, attached to the upper frame whereupon the by the action of the plunger 58 and engaging the cam 13 mounted upon the main drive shaft I6 of the press. The coil sfiing 14 urges the carn follower 12 downwardly against\ the cam 13.

The 'pilotoperated check valve 95 shown in- Figure 8 may be of any conventional type, the details of which form no part of the present invention. The check valve shown for purposes of illustration consists of a casing I50 having threaded connections II and I52 to the pipes 99 and 91, respectively. The casing I50 is provided with a partition I53 with a valve seat I54 engaged by a valve member I55, mounted on the end of a valve rod I56. The latter passes through a bore I51 in the casing I50, into a valve-lifting chamber I58 having a cylinder bore I59. Secured to the opposite end of the rod I56 from the valve member I55 is a piston head-I60, engaged by a coil spring I6I of a pressure sufllcient to overcome the action of gravity and tending to urge the valve member I55 lightly into engagement with the valve seat I54. Opening into the bore I 59 is a port I62 leading to a longitudinal groove I63,which in turn, opens into a chamber I64 formed between the connecting casing I65 and the plug. I66, closing the bore I59 and engaging the end of the coil spring I6I. The casing connection I65 is threaded, as at I61, to a portion of the casing I50 and has a passageway I68 leading therefrom into the pipe I03. 3

In the operation of the circuit shown in Fi ure '1, and during the working stroke, the line 60 from the pump 64 delivers fluid under pressure through the valves 94, Hand 93 and by way of the lines 99, 91 and 96 to and throughthe plunger 51 and the cylinder 53 to the space above the builds up to such an extent that it backs up in the pilot line 98 andoperates the pilot plunger of the pump unloading valve 94, thenceforth causing the line 60 from the pump 64 to discharge its contents into the discharge lines IM and I02, thence into-the tank 84! The further motion of the press'platen 8' then causes the generating plunger 51 to continue to buildup the pressure of the fluid and thereby to force the pressingplunger still further forward. When the pressure of the fluid exceedsthe load setting of the high pressure regulating valve 93 it actuates he latter. causing it to discharge the fluid from the line 96 into the discharge line I00 and thence bv the line I02 into the ,tank 84 until the working stroke of the platen 8 has been completed.

The platen 8 then starts its return stroke, flow from the pump 64 is reversed cam' 13. The fluid under pressure now passes through the line 6 I, the the cylinder 52 into the space beneath the pressing plunger head 48. retracting the latter. Meanwhile the same fluid under pressure backs up in the pilot line I03 to the check valve 95, entering the bore I59 (Figure 8) and urging the piston head I60 outwardly against the urge of the spring I6I, thereby opening the check valve 95 by forcibly lifting the valve member I55 from its seat I54. This allows-the fluid from the space above the pressing plunger head 48 to pass through the plunger 51; the lines 96, '91 and 99; and the valves 93, 95 and 94 to the line 60, thence back to the pump 64. This cycle of operations repeats itself as theplaten 8 reaches its, limits of travel during its subsequent working and return strokes.

It will be further'unders'tood that the auxiliary pressing ram 39 might be placed in the bed 8 instead of in the platen 8, the intensifier rams then being carried by the platen. This arrangement is shown in Figure 5.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In combination in a press, a movable platen, a piston-and-cylinder assembly including a piston member and a cylinder member for generating fluid pressure operated by the motion of said.

platen, one of said members being associated with said movable platen and the other member being mounted in a substantially stationary position relative thereto, and a second piston-and-cylinder assembly adapted to be operated by the fluid from said press-operated means, said second pistonand-cylinder assembly being arranged to provide additional pressing movement to that of said platen.

2. In combination in a press, a movable platen, a frame having a bed, means for generating fluid pressure operated by the motion of said platen, and a piston-and-cylinder assembly adapted to be operated, by the fluid pressure from said platen-operated means, said piston-and-cylinder assembly being arranged between said platen and said bed to provide additional pressing movement to the pressing movement of said platen.

3. In combination in a press, a movable platen, a frame, a cylinder bore within said platen, a plunger reciprocable within said cylinder bore and secured to said frame, said plunger being arranged to oppose the motion of said platen and to compress the fluid within said bore, and a hydraulically-actuated device adapted to be operated by the fluid pressure generated by reason of the relative motion between said cylinder bore and said plunger.

4. In combination in a press, a movable platen, a frame, a pressure-generating piston-and-cylinder assembly including a, piston member and a cylinder member operated by the motion of said platen, one of said members being associated with said movable platen and the other member being secured to said frame in a substantially stationary position relative to said platen-associated member and a second piston-and-cylinder assembly mounted on said platen and adapted'to be operated.relatively to said platen by the fluid pressure from said platen-operated piston-and with said movable platen and the piston thereof being substantially immovably securedto said frame and a second piston-and-cylinder assembly adapted to be operated by the fluid pressure from said platen-operated piston-and-cylinder assembly by reason of the relative motion between said platen andsaid frame, said second piston-andcylinder assembly being arranged to provide additional pressing movement to the pressing'movement of said platen.

6. In combination in a press, a movable platen, a frame, a pressure-generating piston-,and-cylinder assemblyincluding a piston member and a cylinder member operated by the motion of said said pressure-generating piston-and-cylinder assembly by reason of the relative motion between said platen and said frame, said second pistonand-cylinder assembly being arranged to provide additional pressing movement to the pressing movement of said platen, an external source of fluid connected to replenish the fluid in said assemblies, and pressure-responsive means adapted to relieve the fluid pressure in said assemblies when it exceeds a predetermined pressure.

. 7. In combination in a press, amovable platen, a frame, a pressure-generating piston-and-cylinder assembly including a piston member and a cylinder member operated by the motion of said platen, one of said members being associated with said movable platen and the other member being secured to said frame in a substantially stationary position relative to said platen-associated member, a second piston-and-cylinder assembly adapted to beoperated by the fluid pressure from said pressure-generating piston-and-cylinder assembiy by reason of the relative motion between said platen and said-frame, said second stonand-cylinder assembly being arranged to provide additional pressing movement to the pressing movement of said platen, an external source of fluid connected to replenish the fluid in said as semblies, pressure-responsive means connected to said source and adapted to discharge the excessive fluid pressure from said assemblies into said source when it exceeds a predetermined pressure, and means enabling the flow of liquid in one'direction only between said assemblies and sa source..

8. In combination in a press, amovable platen, a double-acting pressure-generating piston-and- ,cylinder assembly operated by the motion of said platen, and a second double-acting piston-andcylinder assembly adapted to be operated by fluid pressure from said pressure-generating assembly.

9. In combination in a press, a movable platen,

a double-acting pressure-generating piston-andcylinder assembly operated by the motion of said platen, said assembly including a piston member anda cylinder member, oneof said members being associated with said movable platen and the other member being mounted in a substantially stationary position relative thereto, and a second double-acting piston-and-cylinder assembly associated with said movable platen and adapted be operated by fluid pressure from said pressuregenerating assembly.

10. In combination in a press, a frame, a movable platen movably mounted on said frame, a pressure-generating piston-and-cylinder assembly connected between said platen and said frame and adapted to be operated by the motion of said platen, a second piston-and-cylinder assembly adapted'to be operated by fluid pressure from said pressure-generating piston-and-cylinder assembly by reason of the relative motion between said platen and said frame, and means to retract the I piston of said second piston-and-cylinder assembly during the returnstroke of said platen, said retracting means comprising a source of pneumatic pressure operatively connected to said piston of said second piston-and-cylinder assembly.

HOWARD F. MACMILLIN. 

